# -*- coding: UTF-8 -*-
from leetcode_helper import TestcaseHelper, SolutionBase, ListNode, list_to_array, array_to_list


class Solution(SolutionBase):
    # 解题的方法，命名和Leetcode的保持一致即可
    def removeNthFromEnd(self, head: ListNode, n: int) -> ListNode:
        node_before_n: ListNode = None
        node: ListNode = head
        count = 0

        while node:
            node = node.next
            if count == n:
                node_before_n = head
            elif count > n:
                node_before_n = node_before_n.next
            count += 1

        if node_before_n:
            node_before_n.next = node_before_n.next.next
        else:
            return head.next

        return head


if __name__ == '__main__':
    solution = Solution()

    # 按照leetcode的题目说明，将基本的test case填入
    # 每条case的最后一个元素是正确的结果，即期待的结果
    # 使用元组来保存输入的数据，期待的结果
    testcases = [
        ([1 ,2], 2, [2]),
        ([1, 2, 3, 4, 5], 2, [1, 2, 3, 5]),
        ([1], 1, []),
        ([1, 2], 1, [1])
    ]

    for case_item in testcases:
        # 获取测试用的case和期待的执行结果

        input1 = case_item[0]
        input2 = case_item[1]

        expect = case_item[len(case_item) - 1]
        exec_result = solution.removeNthFromEnd(array_to_list(input1), input2)

        # 判断执行结果，输出提示信息
        check_result = solution.check_result(expect, list_to_array(exec_result))
        TestcaseHelper.print_case(check_result, case_item, exec_result)

